Initially-tensioned reenforced concrete structure



March 3, 1931. H. soRENsEN 1,794,425 n INITIALLY TENSIONED REENFRCED CONCRETESTRUCTURE Filed Feb. 14, 195o a 5 a A A /3 7 /0 /3 /4 Z m4 7i l /5 y /I/a INVENTOR l Patented Mar. 3, 1931 UNITED STATES HENRY SORENSEN, OF SAN FRANCISCO, CALIFORNIA IN ITIALLY-TEN SION ED REENFOBCED CONCRETE STRUCTURE `Application led February 14, 1930. Serial No. 428,323.

While my invention may be applied to any form of structure for which it is adapted, I have, in the following specification and the accompanying drawings, described my inveny i applied to the floors of iireproof build- In the drawings Fig. 1 illustrates a section of my invention with the various parts in place ready to re lo ceive the concrete. Y

Fig. 2 is the fragment of a longitudinal view, taken at a--a of Fig. 1, but omitting member 14.

Fig. 3 is the fragment of a longitudinal view,taken at b-b of Fig. 1, but omitting member 14.

Fig. 4 is an enlargement of a-a of Fig. 1,

but omitting members 1 and 14.

Fig. 5 is a section of a finished vfloor equipped with my invention. 4

Fig. 6 illustrates a modified construction of my invention.

Similar numerals designate similar parts, and numeral 1 designates a strut. 2 are beams. 3 wooden wedges. 4 strut supports. 5 are bars or flat steel. 6 are separating members. 7 rivets. 8 a beam dan e. 9 openings. 16 reenforcements. 11 reenircement ends. 12 is a loop in reenforcement 10. 13 tensioning members. 14 forms for concrete. 15

18 a Washer.

Referring to Fig. 1, Fig. 2 and Fig. 3, I first place struts 1 between the inside webs of the opposed beams 2. Struts 1 consist of two parts, with wedges 3 intersected between the two parts of 1, so that struts 1 may have a snug fit against the webs of beams 2, when wedges 3 are tapped. Up-

rights 4 support struts 1, and struts 1 are placed at suitable intervals along the webs of beams 2.

I next connect the bars or flat steel 5, by means of rivets 7, through separators 6, to the top flange 8 of one of the two opposed beams 2. Flat steel 5 may be substituted by any other suitable device to cover separators 6. Instead of using rivets 7 I may weld Hat steel 5, separators 6 and flange 8 together. separators 6 are placed at suitable intervals concrete. 16 beam fire-proofing. 17 a nut.

between flat steel 5 and flange 8, leaving openings 9 between Hat steel 5, fia-nge 8 and separators 6.

Reenforcements 10 are each made out of one long rod, which is doubled together in lts middle, so that each of the reenforcements 10 consists of a double rod, having at its one extreme'a loop 1.2, while its other eXtreme consists of the two ends 11; the loop 12, of reenforcements 10, is ings 9.

Thereupon I place the members 13 inside this loop 12 and against the edges of flat steel 5 and ange 8. While holding ends 11 taut, I now tap ends 11 round the edges of the top and bottom flanges of the other of the opposed beams 2, as shown in Fig. l and Fig. 3. Ends 11, by being tapped three times round the ange edges of said beam .2, have a strong grip to resist the draw, which 1s caused by the tensioning of reenforcements 10.

Members 13 consist of two wedgeshaped parts. The one of these two parts of member 13 has rounded edges to fit the inside of loop 12, While the other part of member 13 has a flat surface operating against the edges of flat steel 5 and iiange 8. The two parts of member 13 are wedgeshaped, in their relation to each other, so that they expand when driven against each other.

After the various parts are in place, as above described, I drive the two wedgeshaped parts of member 13 against each other. Due to the fact that the taut reenforcements 10 are held firmly by ends 11, the expansion of member 13 in loop 12,-which takes place when the two wedgeshaped parts of 13 are driven against each other,-will tension and lock reenforcements 10 to the opposed beams 2. I now place forms 14 upon struts 1, and the structure is ready to receive the concrete.

In Fig. 4 I have shown an enlargement of member 13, in its position,just before the two wedgeshaped parts of 13 are driven together,to tension and lock reenforcement 10 to the edge of fiat steel 5 and to the edge of iange 8. The arrows indicate the driving together'of the two parts of member 13. The edge of the fiat steel 5 and the edge of ange passed through openitself, act as a permanent strut to prevent 8 form a rigid base to which I can initially tension and lock reenforcement 10 by means of member 13.

In Fig. 5 I have shown a finished floor, with reenforcemdnts 10, which extend between beams 2, fiat steel 5, separating member 6, member 13, and the top anges of beams 2 embedded in concrete 15, after struts 1, wedges 3, upright supports 4 and forms 14 are knocked down. I protect the lower parts of beams 2,-as well as the ends 11, of reenforcements 10,-against fire by means of beam tire-proofing 16. Instead of concrete 15 I may use any other suitable infilling.

Fig. 6 is a broken connection between beams 2, in which I show a modied construction of m invention consisting of a single,- instead o a double,-reenforcement 10. The one end, of this single reenforcement 10, is threaded to fit nut 17, which operates against washer 18, and washer 18, in turn, contacts the edges of ilat steel 5 and flange 8. The other end, of Vthis single reenforcement 10, is bent round the flange edges of the opposed beam 2, in the manner as previously described. The initial tensioning and locking, of this single reenforcement 10, to beams 2 takes place by tightening nut 17. The edges of flat/steel 5 and flange 8 afford a strong and rigid base against which to tighten nut 17. `In the modified construction as illustrated in `Fig. 6 I have not shown struts 1, wedges 13, upright supports 4, forms 14 or concrete 15, but I use those parts, in this modiied con struction, in the same manner as previously described.

The temporary struts 1 serve the purpose to prevent the draw, of the tensioned reen-A forcements 10, from delectin such deflections would cause t e loss of the tension in reenforcements 10. Struts 1 are not removed before the concrete 15 has set into hard cohesion with the initially tensioned reenforcements 1). After struts 1 are removed the hardened concrete 15 will,

deflections of beams 2. The shrinking force, caused by the reaction of the tension in reenforcements 10, will then in turn permanently clamp the finished steel structure and concrete 15 to ether, and any pressure, from the outside, will first have to take up, or absorb, that reaction, before concrete 15 can commence to feel the pressure.

Due to the fact that bar 5 is rigidly attached to flange 8 by means of rivets 7, which pass through the se arating members 6, the edges of bar 5 and. ange 8 form an absolute rigid base against which reenforcements 10 may be initially tensioned and locked in the manner as already described, there beingno possible movement in bar 5, which could cause the loss of the tension in reenforcements 10. The fact that wedge members .13 rest against two spaced and rigid parts, viz z-bar 5 and bar and said iiange, and inlling em beams 2, as

ange 8, prevents members 13 from twisting or slipping, which would also cause the loss of the tension in reenforcements 10.

My invention affords a rigid and solid grip for the initial tensioning of reenforcements 10, whereby a high degree of initial tension may be injected into the reenforcement steel, and the work is done in a cheap and expedient way.

Various modifications in construction may be made without departing from the spirit of my invention.

I claim 1. In a bar to facilitate the initial tensioning and locking of the reenforcements of an in lled structure to the ange of a beam 'supporting said structure, the combination of spaced members intermediate said bar and said ange, said bar, said members and said flange rigidly connected together, the ends of said reenforcements passed through the openings between said bar, said members and said flange, tensioning means attached to said ends and adapted to initially tension and lock said reenforcements against the edges of said bedding said reenforcements, said means, said ange, said members and said bar.

2. In a bar to facilitate the initial tensionino and locking of the reenforcements of an intdlled structure to the flange of a beam supporting said structure, the combination of spaced members intermediate said bar and said ange, said bar, said members and said flange rigidly connected together, the ends of said reenforcements passed through the openings between said bar, said members and said flange, loops connected to said ends, wedges driven into said loops and contacting the edges of said bar and said flange, and infilling embedding said reenforcement, said loops, said wedges, said iange, said members and said bar.

3. In a bar to facilitate the initial tensionin and locking of the reenforcements of au inlled structure to the fiange of a beam supporting said structure, the combination of spaced members intermediate said bar and said iange, said bar, said members and said flange rigidly connected together, the ends of said reenforcements passed through the openings between said bar, said members and said iiange, threads out in said ends, washers encircling said threaded ends and contacting' the edges of said ange and said bar, nuts engaging said threaded ends and tightened against said washers, and inlling embedding said reenforcements, said nuts, said washers, said ange, said members and said bar.

HENRY SORENSEN. 

